Each of them is a completely different ending to the story. Ending A offers the most closure, and C the least, but you need to see all 3 to fully understand the whole story. The one you read about is C.
If you want to know what happens in each ending, read on. If you want to see them for yourself, don't read this.
(C) Wyl's sanity is slipping. He defeats Lenneth and those he sacrificed who've become her Einherjar. Freya appears and tells him that Lenneth was holding back out of pity, but a Valkyrie's soul is eternal and she will be reborn. Hel knew this all along and was simply using him. Now he's condemned to an eternity in Niflheim. At his house, his sister's music box suddenly falls off the table and Tilte realises he's dead.
(B) Wyl reluctantly fights Lenneth, but Theodor appears as an Einherjar to shield her. He reveals that when Wyl died that day it was Lenneth (not Hel) who brought him back to life. Guilt-ridden over fighting his father, Wyl chooses Niflheim. As Aylith is about to claim his soul, Theodor offers his own soul instead. Lenneth expresses some human emotion over losing an Einherjar, and Wyl is left alone to bear the guilt.
(A) Wyl, guilt-ridden, decides to give up and accept Hel's punishment as atonement for his sins. Aylith is angered and admits that she was the one who caused the war in the first place, as part of Hel's plan to harvest more souls. After defeating her true form (Garm), he gets the chance to speak to Ancel one last time. Ancel, now an Einherjar, forgives him and asks him to tell Tilte he died in battle. He also relays Theodor's final message: to repair the music box.
Wyl finally returns home, lets Tilte know that Ancel is now with the gods and wants her to be happy, and then proceeds to fix the box. As music starts to play, his mother's memories slowly come back and she recognises Wyl's face for the first time since his sister's death.